This invention relates to a novel process for producing alpha,beta-unsaturated ketones. More specifically, it relates to a process for producing alpha,beta-unsaturated ketones starting from alpha-disubstituted-beta-keto acid esters.
Unsaturated ketones such as cyclopentenone derivatives, cyclohexenone derivatives and cyclododecenone derivatives are useful chemical substances in the fields of perfumes, medicines and chemicals.
Recently, a new process for synthesizing such an unsaturated ketone was reported which comprises treating an alpha-disubstituted-beta-keto acid ester with a catalyst consisting essentially of a palladium compound and an alpha,omega-alkylenedi(disubstituted)phosphine (Journal of Chemical Society, 1982, 104, 5844-5846). This document states that the above reaction is a specific reaction which takes place only when the alpha,omega-alkylenedi(disubstituted)phosphine is used as a ligand, and the use of an ordinary ligand such as triphenyl phosphine leads to a different reaction.
Accordingly, in such a prior technique, the ligands that can be used are limited to expensive compounds having a special structure. Moreover, this technique does not prove to be entirely satisfactory in regard to the activity of the catalyst, the selectivity of the reaction and the stability of the catalyst in the reaction system.